Superintendent Grahame Clarke from Police Scotland said: "Public warnings have been issued recently in relation to the dangers of taking ecstasy, or indeed tablets being passed off as ecstasy.

"They are illegal and could contain a cocktail of toxic ingredients.

"We have yet to establish if this particular pill is to blame for the death of this young woman, but the fact that she and her friends took pills described as green and with a Rolex stamp on it causes us real concern.

"The exact contents of the pills are unknown but they could contain dangerous chemicals and users need to be aware of the dangers and understand the devastating effect they can have."

Police have previously warned of other tablets being sold as ecstasy, including a white pill with the Mitsubishi logo imprinted on it. It was found to contain the chemicals 5IT or AMT.

A yellow tablet with a star logo has also been identified as dangerous.

Richard Stevenson, a doctor in emergency medicine at Glasgow Royal Infirmary, said he was “deeply concerned about the number of drug related deaths.”